1. Field of the Invention
The present invention relates to the field of manufacturing of liquid crystal display panel, and in particular to a panel unpacking method and a panel unpacking device.
2. The Related Arts
Liquid crystal display (LCD) has a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and is thus widely used.
Referring to FIG. 1, a liquid crystal display device generally comprises a backlight module 100, a mold frame 300 arranged on the backlight module, a liquid crystal display panel 500 arranged on the mold frame 300, and a front bezel 700 arranged on the liquid crystal display panel 500. The backlight module 100 provides a planar light source of homogeneous illumination to the liquid crystal display panel 500. The mold frame 300 carries the liquid crystal display panel 500. The front bezel 700 retains the liquid crystal display panel 500 on the mold frame 300.
In the manufacture of liquid crystal panel, the first step is to depackage panels (glass substrates). The unpacking process of the panels is using a robot to remove the panels out of a packaging bag one by one and to place the panels on a conveyance device to allow the conveyance device to convey the panels to the subsequent process.
Referring to FIGS. 2-5, in a conventional process of unpacking panels, the operation is as follows. A six-axis robot 900 having end effectors formed of vacuum suction cups 902 to suck and hold a panel 550, followed by lifting. Then, a movement is made by a distance in a direction toward a conveyance device (not shown) and then stopped. The panel 550 is rotated to make upper and lower sides of the panel 550 reversed, whereby the vacuum cups 902 that were originally holding the panel 550 from the upper side are now supporting the panel 550 from the lower side. Next, movement is continued in the direction toward the conveyance device until reaching a location above pins 750 of the conveyance device on which the panel 550 is positionable. Next, the vacuum cups 902 supports the panels 550 and moves downward to stably position the panel 550 on the pins 750 of the conveyance device for supporting the panel 550. The process takes about 30 seconds.
In the above described panel unpacking process, since it includes an operation of rotation, there is a high risk that the panel gets broken in this operation. Since the rotation operation needs a large amount of space, the facility would have a large volume and the panel must be moved for a large distance. In addition, position restoration through rotation is necessary so that the entire panel unpacking process is very complicated and the efficiency of the facility is low.
The reason for rotating the panel is to set the vacuum cups at a location under the panel in order to properly support the panel thereon so that the subsequent lowering movement relative to the pins is carried out to allow the panel to directly contact the pins of the conveyance device that are provided to support the panel and thus stably position the panel on the pins.